RepRap: Blog

This looks terrible, but there was no anticipation of a great success so that's OK. Many variables were changed. The print of a 500μm diameter Micromug was attempted using the new - much faster - segmented plotting algorithm, breaking into 15μm segments with 200 segments per dip. That was ample to complete one perimeter. A little Vivid marker was accidentally added which improved contrast a lot. A simpler slide was used with no folded foil edge, and it just relied on the resin curing in UV as it overflowed.

• 35μm extrusion width
• 3.5μm layer height
• 1 perimeter
• 15μm nozzle diameter
• 1 solid bottom layer
• Random seams 

One improvement was taking screenshots from the side view camera during layer curing. This allowed me to compare the speckled reflection of the UV LED from one layer to the next. No change in image means no new material added.

The probe was cleaned off with IPA and a tissue afterwards. I'll deliberately paint the probe with a Vivid next time, as Probe 9 is robust enough to survive this.

If at first you don't succeed, try again at greater speed. 

# posted by vik-olliver @ 8:49 PM 0 comments

I've found the maximum speed I can run at without causing excess vibration: 8mm/min. I noticed the probe accidentally touched the slide when I was moving at 14mm/min doing some tangram shapes, so I did a bit of experimenting.

To find out what the speed limit is, pick your safe Z height -  the height to which you feel happy raising your probe between moves. In my case this is 35μm. Then you put a slide covered in Sharpie marker under the probe at that height, and start issuing manual GCODE commands to move 500μm at ever increasing speeds until your motors slip or the probe vibrates so much that it whacks into the slide.

Here's my test. You can see the horizontal lines moving in a square pattern where the probe starts digging in.

This was with Probe 9. I haven't tried this out with other probes, so I don't know if this is a probe vibration issue or a structural vibration issue.

It occurred to me that if I'm drawing with resin rather than placing dots, I'm not so fussed about micron accuracy. That's because my plot is going to need to be 30-40μm wide to have structural strength. So if the probe drifts by 5μm I don't care at that resolution.

Soooo, I can just draw lines rather than do little dots. I'm modifying the "dipify" code to support that straight out of PrusaSlicer. I still need to break the GCODE lines up into short segments so that I know when to go and dip the probe in more resin.

Still, it should speed things up a bit when printing. I can switch back to dots if I need more accuracy or have a more wobbly probe.

# posted by vik-olliver @ 6:24 AM 2 comments

Sometimes your experiments do not prove your hypothesis. This is one of those. You have to remind yourself that it didn't "fail" it just returned unexpected results.

After trying to draw solid lines with resin and getting no adhesion from the Dutch Guilding (UNAOIWN Gold foil GF01 AU) I just went medieval on it and put down blobs of resin. Then I dragged out one of those blobs into thin lines with the probe. The foil was then laid down, pressed with a lightly compressed tissue, placed under a sheet of paper, and burnished with a chromed rod. 

Burnishing was used as the foil has a very dimpled texture and there was no other readily apparent way to ensure good contact with the resin on the slide. That should fix it.

After plentiful exposure to UV from underneath, the slide was rubbed first with a brush, then a cotton bud. Much foil randomly adhered to the slide. I rubbed much harder. The slide was then examined under the microscope:

As can be seen, adhesion by the foil to the resin is more or less random (the circular structure is part of the slide support). There was very little correlation between any of the resin blobs and the locations of patches of foil, some appearing stuck down with optimism and stubbornness on areas that had not acquired resin.

As well as being dimpled, the material appeared to fracture easily into straight-edged flakes with a distinct grain, in a way that real gold foil does not. 

So, not much of immediate use here. But I do have plenty of guilding for Christmas decorations. Might try using the probe to machine the foil later, so I'll hang on to a few sheets.

Real gold foil may be obtained later, and I suspect that will behave somewhat differently. 

# posted by vik-olliver @ 10:57 PM 0 comments

Dutch Guilding is used as a cheaper and more amateur-proof alternative to gold leaf. It's a form of very thin brass sheet, therefore conductive and non-edible. Although thicker and sturdier than real gold, it is still inadvisable to leave the book of it open on your desk when you turn on the air conditioning. Ask me how I know.

The hypothesis was that it would be possible to adhere guilding to the glass slide using deposited UV resin. Previous rough tests were inconclusive, though resin was observed on the resulting fragments of leaf.

I printed an 8x8 hollow square at 50μm spacing using Probe 9, allow a 25mm square of generic Dutch Guilding leaf to lay itself onto the pattern, and pressed it carefully with a loosely-wadded tissue. Then I pressed more firmly, taking care not to push sideways.

Finally, I transferred this to a UV lamp and cured the resin excessively.

A bit of a null result. I suspect that the resin adheres more strongly to the leaf than to the glass, and when I peel the leaf off, the resin sticks to that. This may be useful at some stage, but it isn't right now.

I did manage to make a test blob approx. 0.5mm diameter stick to the glass. This suggests that the force necessary to peel the resin off the slide for a given area needs to be greater than the shear force concentrated at the edge of the resin blob. The leaf then tears, and the resin remains on the glass. Maybe.

So basically, try bigger blobs (or more dense dots, or both). On the plus side, this should work somewhat better with actual gold leaf, as this is an order of magnitude more fragile than Dutch Guilding leaf.

# posted by vik-olliver @ 3:42 AM 0 comments

I put the RepRapMicron through a few more paces and found the Axis Driver I had fitted wasn't quite concentric and didn't have enough tension on the anti-backlash bands. Here's how to fix:

Then loosen the two screws next to the bands a bit so that the bar supporting the bands can be moved around. While driving the axis, adjust the position of the bar for minimum unwanted wriggle of the drive screw. I do this by watching the squared protrusion that contacts the limit switch. When it is in a good position, carefully tighten the two screws again.

I tighten the screws in gentle increments alternately until they're tight. This will all minimise unwanted axis deviation. It's a shame this is still necessary, but at least it's much simpler to do than the previous Axis Driver design!

# posted by vik-olliver @ 8:14 PM 0 comments

While looking for reference images I came across the technical paper that started it all for me: The technical report on the original Meccano RepRap proof-of-concept. For those interested, I've put the document up on ResearchGate https://www.researchgate.net/publication/398027280_Construction_of_Rapid_Prototyping_Testbeds_Using_Meccano

I already had a company called Diamond Age back then. Marvel on how things have gone in the last couple of decades.

# posted by vik-olliver @ 7:46 AM 0 comments

It's been a while coming, but at last I have managed to do multiple layers. The big question is: How many? Well, about 10 before things turned to custard on this attempt. But the custard was very informative. Take a look:

In the middle we have a 400μm long (i.e. 200μm diameter) lollipop made with layers 4μm high and assuming a 30μm wide dot size. I got a few layers in before I noticed irregularities around the circumference which you can just make out. This was where the probe was not touching the surface below and so no resin was transferred.

A few notes:

First, it is really, really hard to see the layers or indeed what is going on. So it is not obvious when the RepRapMicron is not working. Consequently things can go hilariously wrong and you can't tell until you take the slide off, tilt it sideways, and shove it under the big microscope.

Secondly, it appears that any defect in the layer tends to accumulate resin. This means that if all your print seams line up, a really big defect will happen (I'm looking at you at the back). So, lesson learned, stagger your print seams. When the probe goes to dip and recharge with resin, that can create a seam too - that's where the biggest blob came from. It may be that making sure the probe runs out of resin will lessen this problem.

Kinda related to that, the first resin drop is always a bit big. It may be necessary to make some form of print tower ("The Tower of Ooze" as we called it way back) to get rid of that.

Finally, the probe is not just brushing the upper surface. It is stabbing in to semi-set resin. On that scale the resin doesn't just run downhill because surface tension is having a massive effect on the resin - far more than gravity. So your resin will stick to the top surface, the side of a surface, or any damn where it comes into contact. This may be useful for bridging later.

Back to our picture.

Bringing up the rear is a 500μm diameter single-walled cylinder with some kind of blob sticking out the top. That was done at 3.5μm per layer with an assumed dot size of 40μm ,and a dot spacing of 15μm. It was depositing 60 dots between dipping the tip. Every time it was dipping, the dip code briefly turns the UV LED on to gel the already deposited resin.

That one got to about 10 layers. You can see the top surface (ignoring the darn blob from the seam problem) has a square edge, not a rounded one. This indicates that layering is happening rather than I'm just making a thick line - there is no surface tension curving the upper surface.

So by that reckoning that cylinder is roughly 35-40μm high, and the deposited line is roughly 40μm wide. Which looks about right.

For a first stab at a multi-layered object from an STL file I'm pretty pleased with that result. A slightly thinner or more steeply angled probe tip, staggered layers, a more accurate measure of how many dots per dip, some kind of method of knocking off the first dot from the probe, and I think we can get better resolution and significantly more than 10 layers out of this. Maybe overhangs too.

# posted by vik-olliver @ 7:21 AM 3 comments

Just a quick update. Fitted the Axis Driver that I just made for Siddharth's photos. Moved straight and homed first time! Note that I had previously moved the black bracket it is attached to up one hole when fitting the previous test axis. I haven't fitted the booster that increases the band tension, but that can be slipped in later if needed.

• Make a new slide.
• Test layers with Probe 9.
• Finish Everything Open presentation script. 

# posted by vik-olliver @ 12:03 AM 0 comments

Carrying on from a couple of posts back, here are the remaining stages of assembly for the RepRapMicron V0.05 Axis Driver.

The things not obvious from the photos are:

• The red Flexure Coupling on the motor is in a separate OpenSCAD file.
• You can use different height NEMA17 Plates to match the length of your motor's shaft.
• Adjust the position of the pair of locknuts so that the base of the Drive Screw goes into the hexagonal socket on the Coupling. 
• Very lightly oil the drilled-out M3 nut bearings, the M3 x 50mm Drive Screw, and its washers. 

Pipe up if I've missed anything.

Labels: driver, Pantograph, reprapmicron

# posted by vik-olliver @ 1:15 AM 0 comments

Not my own work, but these enterprising people have adapted the mouthparts of a dead mosquito into a fine extruder nozzle, getting down to 20μm. An interesting approach. While not one we might use immediately (though do go ahead if it tickles your fancy), it does demonstrate that we can nick bits from nature if that's what it takes. I'm quite interested in the delicate silica structures of diatoms myself.

Screenshot from https://techxplore.com/news/2025-11-repurpose-mosquito-proboscis-3d-nozzle.html below.

# posted by vik-olliver @ 1:06 AM 6 comments

Siddharth pointed out that the assembly of the Parallelogram Axis Driver isn't shown anywhere. Pending proper documentation I've taken a bunch of photos for the tricky bits.

I updated the OpenSCAD files an hour ago.

Probe 9 has been checked under a microscope after the last test, and it stood up well to being cleaned with isopropyl alcohol and the corner of a tissue. 

Hospital visit did not go as expected and I'm minus a couple of strips. Going to take a few weeks to heal up. 

# posted by vik-olliver @ 3:48 AM 2 comments

The plan was to make Probe 9 out of 0.13mm dia Nicrome 80 but that cut through very, very quickly at the meniscus when I tried etching it in nitric acid. Probably because I didn't dip it in far enough (my discoveries on etching dynamics are for a later post). Change of plan.

A length of 0.3mm dia 316 Stainless wire was immersed in the 0.5% nitric acid probe etching cell by approximately 10mm, and electrolysed for approximately one minute. The wire was checked twice, and etching was stopped when a noticeable tip had formed. By this time the sides of the wires were roughened.

The wire was then taken to a second cell containing a 5% sodium chloride solution with 0.5% hydrochloric acid. The wire was connected to the anode as usual. The very tip of the wire was then touched to the surface of the electrolyte in the cell for approximately 5 seconds, then examined under a microscope. This was repeated three times. When the probe tip had acquired the desired ogival point, the probe was washed with water, then isopropyl alcohol.

The tip was mounted in the RepRapMicron V0.05 Probe Tip Arm with cyanoacrylate adhesive. A micrograph was taken, the Probe Tip Arm was fitted to the μRepRap, the tip dipped in approximately 0.5mm of "Top Coat" resin, and another micrograph taken:

Probe 9 was refitted to the μRepRap, touched off on a glass slide coated with Vivid marker, and then repeatedly touched off at 40μm intervals. The intervening height was 20μm to avoid probe or fluid drag. The slide was then micrographed at the same magnification as Probe 9:

The first few dots (left) are a little larger than the others. The rest seem a relatively consistent size. The experiment was terminated after approx 60 dots (some are out of view) due to time constraints, and resin was still being deposited.

The dot size is clearly less than 40μm, though due to the optics and imaging used the exact dimensions are not apparent. It would appear to be in the order of approximately 20μm. This is adequate, and Probe 9 will be used for layer experiments.

Unfortunately, I'm going to have to leave you with a bit of a cliff-hanger because I have to do more hospital things for a few days. I fully expect to return. Might write a few more things up while I'm gone. 

# posted by vik-olliver @ 3:49 AM 4 comments

The resin-carrying and deposition characteristics of the probe need to be a little more quantitatively defined. To define this we need something with a simple geometry. Enter Probe 8, made from 0.13mm dia. Nichrome 80, etched in 1% nitric acid. Like previous nitric-etched probes, the point is pretty blunt, at approximately 90 degrees. If 5mm of wire is in the electrolyte, it cuts through at the meniscus in 30 seconds or so.

The probe was removed and examined periodically during etching without any particular goal other than having some kind of simple point and not thinning excessively. Approximately 5mm of wire was in the electrolyte, and total etching time was in the order of 30-40 seconds.

The slide was coated with a small amount of Vivid permanent marker to make things easier to see, and a smear of Top Coat applied nearby.

The probe was put in in the RepRapMicron, dipped in Top Coat resin, and micrographed. It was then stuck it back in the RepRapMicron which was manually controlled to drop a sequence of resin dots at 40μm intervals, skipping to 20μm high in between dots to make sure the probe was not simply dragging resin. The result:

The probe has deposited 11 dots of fairly consistent size, then the width tapers off. The approximate width of the joined line of dots is 60μm, and the length ~160μm.

In conclusion, this is still depositing lines a bit thicker than we want. I'd hypothesise that a slightly sharper angle on the point would create a smaller dot size.

I'm unsure what to expect if the probe diameter was reduced instead. The size of the line probably relates to the angle between the sloping probe tip and the glass slide, in which case the line width would be largely unchanged, and fewer dots could be deposited using the resin coating the probe. This seems to be supported by the results from Probe 1 which produced similar line widths while being 0.3mm diameter.

It may be possible to achieve smaller dots by etching some 0.13mm Nichrome 80 in nitric acid to develop a relatively blunt point, and then switch the electrolyte to NaCl/HCl to sharpen it slightly. Even if the thinning at the tip is drastic, this will increase the distance between the face of the tip and the slide, which would also reduce the diameter of the deposited drop. It will require constant checking during the etch. I might try that next. 

# posted by vik-olliver @ 11:51 PM 0 comments

The amount of resin that clings to the surface of the probe is quite small. In this particular case, too small. Most people envisage a hanging droplet, but that's not what happens. First off, the effects of gravity are minuscule on this scale compared to molecular attraction, so things don't hang like you'd expect. Secondly, this is a capillary effect and only the last 100μm or so of the probe has anything on it. Here is a micrograph of Probe 7 before and after dipping in a film of resin:

Welcome to the weird world of tiny. 

By the way, this is how I position things at odd angles under the trinocular microscope. I use 10 gram 9mm lead bullets with sticky wax on their bases and a piece of perforated acrylic sheet  that can be moved around underneath the microscope without disturbing the pile of bits. Works remarkably well.

# posted by vik-olliver @ 4:18 AM 0 comments

Probes etched in nitric acid tended to have a short, stumpy tip with rough sided. I'd found that adding hydrochloric acid to the salt etch removed cloudy precipitates, but the concentration I used was way lower than with nitric acid. So I etched Probe 7 using 50ml of 0.5% hydrochloric acid and 2 grams of salt. I also reduced the submerged length of the probe wire to 6mm.

The etch released noticeably more gas on the cathode, and the etched wire broke off just below the meniscus. For scale, that's a 0.3mm diameter 316 stainless wire:

I'm constantly surprised at the variations produced by merely changing the etching electrolyte. Good job I'm using a consistent electrolysis rig or I'd wonder what they heck was going on.

Again, the actual tip on this one is sharper than I intended. I was expecting it to have a more rapid taper like the nitric acid etched ones. However, it looks like it might be a very robust geometry, so I'm going to test it anyway. Time to mount yet another probe tip, which is much easier now I have the printed jig and less likely to result in probe destruction.

# posted by vik-olliver @ 11:05 PM 0 comments

There was a minor oopsie and I bent Probe 6. There was swearing. There was also blood. Well, I had microscopes on hand, and I know how to make a blood smear. So here's the bent probe tip. The wee circular things are red blood cells (which don't look so red in ones and twos).

Bear in mind that Probe 6 was not made to be a particularly fine RepRapMicron probe and that a red blood cell of a more or less human is 6-8μm in diameter

# posted by vik-olliver @ 6:34 PM 0 comments

With the relatively thin Probe 6 fitted, a new slide was inserted and all axes zeroed, together with Z Touch.The extrusion width in PrusaSlicer was adjusted to "1.5" (15μm) and the test "Lollipop" printed. The first layer printed perfectly, however the layer height was set to 10μm which proved to be too high and subsequent layers did not print. Images here taken at a 70 degree angle to give some impression of depth.

A 200μm hollow cylinder with 2 solid bottom layers was designed as the next test object, the "dipify" script modified to expose the resin to UV briefly during dips to stop the resin running around, and the second attempt was made to print. This appeared to create the first 2-3 layers, and the bottom infill can be seen:

It appears that the software modifications are useful, but Probe 6 is too thin to hang on to a decent amount of resin.

Next steps:

• Put dipify code on github. 
• Make another slide.
• Make a slightly thicker probe.
• Retest. 

# posted by vik-olliver @ 10:30 AM 0 comments

I have now posted the results of FPath Experiment 010. In this experiment a small stepper motor driven XY stage was created out of the medium linear actuators (documented in Experiment 008) and some LEGO bricks. 

The controlling software for the FPath project was improved and it can now position a small tool (represented in this experiment by a segment of 100 micron wire) with about 10 micron accuracy. This can be done manually (using the WASD keys) or via automatic target seeking behaviour. Furthermore, this target seeking algorythm has been extended to demonstrate path following.

I just thought that some of you might be interested in how it was done. The video explains all: https://youtu.be/rHwGZN5nuRI 

The image below shows the little COTS XY stage. (click on the image to enlarge, watch the video for context) 

# posted by OfItselfSo @ 4:09 PM 2 comments

Hydrochloric acid (Spirit of Salts) is easier to get than nitric acid because people don't tend to make explosives from it, and it is widely used in the building industry for removing concrete splat. So I tried using that to prevent the cloudy precipitate when etching a probe and it worked just fine.

I used 40ml of 5% salt solution with 5ml of 0.5% hydrochloric acid to etch a 0.3mm dia. 316 Stainless wire probe as per earlier. The result came out a bit finer than I intended, but I waited for the end of the wire to fall off and it didn't. So, um, less etch time on the next go perhaps?

Anyway, here's the point compared to a 0.5mm hypodermic needle:

[EDIT] This is now mounted as Probe 6.

I might manage slightly finer detail with that. But as I need the nail gel parts to be at least 30μm thick, this point may be overkill. Still, I've made it so I'll mount it and we'll smash it up once I've got my ducks in a row for the next attempt at layers.

Oh, I definitely need a better USB microscope over the RepRapMicron. It's nigh on impossible to see the resin dots. I might try shaving the end of the housing off this one so I can get it closer to the probe tip. 

# posted by vik-olliver @ 4:03 AM 2 comments

I kinda got some layers in a recognizable form. This attempt was a shakedown of the hardware and software pending the fitting of a finer probe. There were two print attempts of a 400μm "lollipop" sliced with PrusaSlicer and the dipify_gcode.py script with Top Coat nail resin. I changed the dipify script so that the reservoir is now at (0,-1000), and as long as I set (0,0) past the edge of the foil reservoir the probe should get dunked.

The first one was intended to be 35μm tall in 10μm layers, the second 50μm tall in 8μm layers. Neither worked to plan. I tilted the slide under the trinocular microscope so you can get some idea of it in 3D:

It's covered in gelled resin (which mostly washed off). This caused it to dump a lot more resin than intended on the second object. In the future I'll have to get the probe lower and further back to stop the reflected UV from gelling the resin.

Here's what it looks like from the top. Remember, the circles are 0.2mm across in this one:

• Label and store this attempt.
• Make a new slide.
• Make a new probe.
• Modify dipify script to lower probe before UV exposure.
• Try again. 

# posted by vik-olliver @ 9:26 PM 1 comments

I've sorted out a niggle with the RepRapMicron's ground plane. It was tiresome to get the spring-loaded clip onto the aluminium foil that's used as a reference touch plane and UV shield for the reservoir. I've soldered the ground wire to the M8 washer that magnetically clamps the slide down. You clamp the slide in place, and it's grounded!

As I've increased the length of the slide covered in foil from 25mm to 30mm, the edge of the foil/reservoir can go right up to the UV LED, with the probe at (0,0). This means I do not have to set the reservoir location in code every single time. I just relocate the part on the slicer's print bed. I get more working volume too.

You do have to make sure the probe goes a fair bit over the reservoir to stop the UV LED underneath setting the probe tip into a solid block!

The "dipify" code had a round of debugging, mostly to do with maintaining safe Z height.

I'll try the new slide and the latest dipify out before making a finer probe.

# posted by vik-olliver @ 2:51 AM 0 comments

No image to show, this is all software. The new dipify PrusaSlicer filter is now on github https://github.com/VikOlliver/RepRapMicron/blob/main/gcode_segmentation/dipify_gcode.py

It now handles layers and turns the UV LED on between them. There is also a scaling factor to deal with PrusaSlicer's assumptions about how big extrusion widths and layer heights can be.

All the parameters are internal, but I've started adding an argument parser. It's not actually used or called yet. 

I've run it through the V0.05 hardware dry, and it doesn't seem to do anything particularly stupid. Now to get the probe and slide hardware sorted out as per previous post so that I can do some layers. That's going to take a day or three...

# posted by vik-olliver @ 2:53 AM 3 comments

PrusaSlicer, bless it's heart, can't cope with the concept of a 6mm print head. As I'm aiming for a 15-30μm line width, that means I can't run the slicer on a scale of one millimetre to one micron.

Back in the RepRap days all this was easily configurable by the user, because nobody was sure exactly what 3D printers looked like yet. Now things are more specialised and gymnastics are needed to cope with exotic extruder sizes.

I'm changing the "dipify" GCODE converter to rescale slicer output. That way I should be able to use probe deposition size values that give sensible layers. I'll start with a scale of 1mm to 10μm and see how it goes.

Other To Do items:

• Detect new layers and modify the Safe Z height as the object gets taller.
• Automatically stow the probe and expose the part to UV in the sliced GCODE.
• Make a slightly finer probe to get dots in the 15-30μm range.
• Design a slide/ground probe with a more conveniently located Z Touch plate. 
• Make a 3D test object (minimug?).
• Establish a practical layer height.
• Maybe speed things up a bit.

Then I can move on to layered objects.

I tried writing a program that watches the probe and detects the flexing that occurs when the probe contacts the slide. Turns out that while the Mk I Human Eyeball can do this, a program has problems with all the video noise. I learned a lot about USB video devices under python though and may be useful later when controlling printed mechanisms:

Oh, I have to deal with writing the Everything Open presentation, and deal with the "Silly Season" that is looming upon us. Jingle Bells and all that. 

# posted by vik-olliver @ 6:13 AM 0 comments

Using OXX Cosmetics UV Gel Top Coat (acrylates copolymer, hydroxypropyl methacrylate, hydroxycyclohexyl phenyl ketone) I wiped off the applicator brush on the brim of the container and touched the slide. With Probe One I printed what I'm starting to think of as the "Test Loop." I printed a few other bits and pieces, interlocking 80μm and 30 μm test squares, blobs etc., and cured the whole thing. First for 30 seconds with the built-in LED, then for 200 seconds on a 4W UV LED lamp. No significant shrinkage was observed.

The Test Loop consists of a nominal 100μm diameter circle with a 100μm line sticking out of the side. That's pretty much what I got. Note that this was done with two perimeters and 5μm intervals between dots. I could easily get 30 dots between dipping Probe One in the reservoir.

Under the trinocular microscope at 100x I tried to lift some test pieces of print with a hypodermic needle tip. They were not wet, but they did not stay together when poked. They were stuck flat to the glass slide. Fragments attempted to straighten out, so they were not in gel form. I had been printing for over 3 hours at this point, so the Top Coat definitely cures after prolonged exposure.

I went to the (now hardened) reservoir blob and pried the edge of that up. The thin edges tore, so I started prying at it until I found a piece that could be considered strong enough to peel away from the glass slide in a sheet. The material was quite flexible and could be bent over on itself. It returned to its original shape quite positively if slowly when released.

I propped up a torn segment on a 0.7mm diameter pin to get a look at the thickness:

The minimal durable film thickness appears to be approximately 30μm. I tried to determine the thickness of the printed Test Loop. Fragments edge-on were beyond the resolution of my optics. This would put the printed layer at very roughly 10μm or less.

Slicing Problems

While the probe dipping code works, and the PrusaSlicer integration is fine, the slicer doesn't accept layer and line thickness proportions that can be used on a scale of 1mm = 1 micron. I'm going to have to add some scaling to do layers, or use the PNG to GCODE script to stack my own. Possibly both. Also having to specify the reservoir location in the script each time I slice is a pain in the butt. May need to change the reservoir location to something closer to XY=(0,0).

Conclusions

UV Nail Gel Top Coat is a viable material for resin printing tests in air, though repeatable layering is yet to be accomplished.

With UV resin there seems little point in trying to print details much finer than 40μm at this stage as they are not robust enough to survive being detached from the glass slide with the equipment I have.

With 30μm voxels, it would take approximately 1mm^2 to make a complementary flexure that could move +/- 40μm. That would take several hours to print each layer at current speed, though that could be improved as micron precision is not required.

Probe One is a little too coarse for optimal resolution given 30μm voxels. 

Given a maximal thickness of the printed layer of 10μm and a minimal viable mechanical thickness, any printed object needs to be at least 3-4 layers thick to survive manipulation.

# posted by vik-olliver @ 8:07 AM 0 comments

Before starting the "Top Coat" nail resin tests, I thought I'd check the state of Probe One (acid/salt etch on Nichrome) to see if it was still in good shape after being used for all experiments since the 17th October. Well, yes. 

I haven't been treating it particularly gently. I have been cleaning it with an isopropyl alcohol spray. But then I've been gently wiping it dry with the corner of a Sorbent white tissue. It's stood up better than anticipated, and the surface still seems to have pores in it.

# posted by vik-olliver @ 2:00 AM 0 comments

That XY Table I said "Don't print this model, it's only a mockup"? Well, I had the model and there was a printer next to me. It kinda happened. In my defence I only printed it at 60% scale.

If you're also going to not print it, I warn you that my flexures were just eyeballed for the sketch and are too thick causing unwanted resistance/rotation. Also it needs a base of some kind (preferably with diagonal bracing) to stop the bent flexures digging into the floor. Other than that it moves surprisingly well, no sagging and the centre stays level when you move it about.

As I say, needs connections and mounts for axis drivers. But, uh, wow. Useful exercise. I'll keep it around to model in OpenSCAD if nobody else does it hint.

Now, stop playing with it Vik, and get on with the resin experiments. 

# posted by vik-olliver @ 7:09 AM 1 comments

I've had this buzzing around my head for a bit. By clever arrangement of the flexures, I think it might be possible to print-in-place the XY Table. So I roughly (really roughly) drew this up in Tinkercad, which is really quite good for 3D sketches:

If you fancy tinkering yourself or looking at a 3D view, I've stuck it on the Fab Lab's public area: 

https://www.tinkercad.com/things/dTJWUZJloZ0-reprapmicron-xy-flexure-mockup 

Attaching the X & Y Axis Drivers is left as an interesting exercise to the enthusiast. Again, this is just a rough mockup of an idea. It's not meant to be a real printable thing. Do feel free to fix that... 

# posted by vik-olliver @ 3:20 AM 0 comments